The invention relates to substrate polishing techniques, including chemical mechanical polishing (CMP).
Chemical mechanical polishing is a process by which a substrate surface is smoothed (planarized) to a uniform level by a polishing pad and an abrasive slurry. A substrate to be polished is usually mounted on a rotatable carrier head and pressed against a rotating polishing pad. The polishing pad typically consists of a disk with a roughened surface. An abrasive chemical solution (slurry) is deposited onto the polishing pad to achieve a desired substrate surface finish. Over time, the polishing process glazes the polishing pad and creates irregularities in the polishing pad surface that can adversely affect the substrate surface finish. The polishing pad surface is typically "conditioned," whereby the polishing pad surface is deglazed and surface irregularities are removed, by scouring the polishing pad surface with an abrasive device known as an end effector.